The City Council voted Monday night to adjust the rates upward — as typically happens this time every year — to cover debt service and capital improvement costs for the water, sewer and stormwater systems.

The new rates are expected to provide revenue increases of 3.55 percent for the water fund, 5.33 percent for the sewer fund, and 6.95 percent for the stormwater fund.

Mayor John Hieftje noted the city is in the middle of a more than $100 million project to rebuild half the city's wastewater plant. He said the city also has other major capital projects on the horizon, including work at the city's water treatment plant.

The city also is dealing with the fact that underground water and sewer pipes installed many decades ago have aged and must be replaced.

"When you get work done, it costs money," Hieftje said. "In order to have new water mains, in order to build a new section of our sewage treatment plant that was originally built in the 1930s, it requires funding."

The city last increased water and sewer rates by about 3.6 percent in 2013, which was estimated to cost the average homeowner an extra $20.66 per year.

In 2012, the city raised rates 3.2 percent, which was estimated to cost the average homeowner an extra $19.40 per year.

In 2011, the city raised rates 3.2 percent, which was estimated to cost the average homeowner an extra $18.92 per year.